1Department of Therapeutic Radiology Gyeongsang National University, College of Medicine, Gyeongsang Institute of Cancer Research, Chinju, Korea. 2Department of Anatomy, Gyeongsang National University, College of Medicine, Gyeongsang Institute of Cancer Research, Chinju, Korea.

ABSTRACT

We studied the T lymphocyte and its subpopulation percentage change in 40 patients immediately after the radiation therapy. Study population consisted of 12 patients treated at the site of head and neck region, 14 patients treated at the site of thoracic region, and 14 patients treated at the site of pelvic region. Twenty two patients received radiotherapy as radical modality, and remaining 18 patients received radiotherapy as postoperative modality. Immediately after radiotherapy, total T lymphocyte (T1) percentage was decreased from 36.4% to 34.1%, but suppressor T lymphocyte (T8) percentage was increased from 23.5% to 25.4%. As a result, T4/T8 ratio was decreased from 1.57 to 1.39. This study suggested that immediate change after radiotherapy of the T lymphocyte and its subpopulation percentage was not related to the treatment volume and the degree of helper T cell decrement was not pronounced by the radiation does increment. Longterm follow-up study in larger scale is needed to determine long term changing pattern in T lymphocyte subpopulation and its relationship to the prognosis of patients.